From: Nishanth Menon <nm@ti.com>
To: Pavel Machek <pavel@ucw.cz>, <pali.rohar@gmail.com>,
<sre@kernel.org>, kernel list <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
<linux-omap@vger.kernel.org>, <tony@atomide.com>,
<khilman@kernel.org>, <aaro.koskinen@iki.fi>,
<ivo.g.dimitrov.75@gmail.com>, <patrikbachan@gmail.com>,
<serge@hallyn.com>
Subject: Re: Can not play audio with screen off
Date: Mon, 16 May 2016 09:22:46 -0500 [thread overview]
Message-ID: <5739D7B6.7060102@ti.com> (raw)
In-Reply-To: <20160515193106.GA18685@amd>
On 05/15/2016 02:31 PM, Pavel Machek wrote:
> Hi!
>
> I'm playing some more with N900, this time I'd like to use it as a
> alarm clock...
>
> And now I realized I can not, because system performance is so
> horrible with screen off that mpg123 + pulseaudio skips horribly. This
> is without tweaking serial parameters, so CPU is definitely not going
> into the idle/off modes.
>
> Loading CPU fixes the issue (I used cat /dev/zero > /dev/null).
>
> Hmm. And it seems to work better if I ssh in and launch mpg123
> remotely. Weird.
>
> Kernel 4.5-rc0. Will try on different ones.
>
> Any ideas? Is there interface to tell kernel that better performance
> is needed for a while?
>
pm_qos cpu_dma_latency? Drivers will have to be properly instrumented
with appropriate latency values -> this will control the depth in C
states that the system will attempt. NOTE: it is a dual edged sword,
bad configurations can result in none of the C-states being entered.
--
Regards,
Nishanth Menon
WARNING: multiple messages have this Message-ID (diff)
From: Nishanth Menon <nm@ti.com>
To: Pavel Machek <pavel@ucw.cz>,
pali.rohar@gmail.com, sre@kernel.org,
kernel list <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-omap@vger.kernel.org, tony@atomide.com, khilman@kernel.org,
aaro.koskinen@iki.fi, ivo.g.dimitrov.75@gmail.com,
patrikbachan@gmail.com, serge@hallyn.com
Subject: Re: Can not play audio with screen off
Date: Mon, 16 May 2016 09:22:46 -0500 [thread overview]
Message-ID: <5739D7B6.7060102@ti.com> (raw)
In-Reply-To: <20160515193106.GA18685@amd>
On 05/15/2016 02:31 PM, Pavel Machek wrote:
> Hi!
>
> I'm playing some more with N900, this time I'd like to use it as a
> alarm clock...
>
> And now I realized I can not, because system performance is so
> horrible with screen off that mpg123 + pulseaudio skips horribly. This
> is without tweaking serial parameters, so CPU is definitely not going
> into the idle/off modes.
>
> Loading CPU fixes the issue (I used cat /dev/zero > /dev/null).
>
> Hmm. And it seems to work better if I ssh in and launch mpg123
> remotely. Weird.
>
> Kernel 4.5-rc0. Will try on different ones.
>
> Any ideas? Is there interface to tell kernel that better performance
> is needed for a while?
>
pm_qos cpu_dma_latency? Drivers will have to be properly instrumented
with appropriate latency values -> this will control the depth in C
states that the system will attempt. NOTE: it is a dual edged sword,
bad configurations can result in none of the C-states being entered.
--
Regards,
Nishanth Menon
WARNING: multiple messages have this Message-ID (diff)
From: nm@ti.com (Nishanth Menon)
To: linux-arm-kernel@lists.infradead.org
Subject: Can not play audio with screen off
Date: Mon, 16 May 2016 09:22:46 -0500 [thread overview]
Message-ID: <5739D7B6.7060102@ti.com> (raw)
In-Reply-To: <20160515193106.GA18685@amd>
On 05/15/2016 02:31 PM, Pavel Machek wrote:
> Hi!
>
> I'm playing some more with N900, this time I'd like to use it as a
> alarm clock...
>
> And now I realized I can not, because system performance is so
> horrible with screen off that mpg123 + pulseaudio skips horribly. This
> is without tweaking serial parameters, so CPU is definitely not going
> into the idle/off modes.
>
> Loading CPU fixes the issue (I used cat /dev/zero > /dev/null).
>
> Hmm. And it seems to work better if I ssh in and launch mpg123
> remotely. Weird.
>
> Kernel 4.5-rc0. Will try on different ones.
>
> Any ideas? Is there interface to tell kernel that better performance
> is needed for a while?
>
pm_qos cpu_dma_latency? Drivers will have to be properly instrumented
with appropriate latency values -> this will control the depth in C
states that the system will attempt. NOTE: it is a dual edged sword,
bad configurations can result in none of the C-states being entered.
--
Regards,
Nishanth Menon
next prev parent reply other threads:[~2016-05-16 14:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-15 19:31 Can not play audio with screen off Pavel Machek
2016-05-15 19:31 ` Pavel Machek
2016-05-16 14:22 ` Nishanth Menon [this message]
2016-05-16 14:22 ` Nishanth Menon
2016-05-16 14:22 ` Nishanth Menon
2016-05-16 15:06 ` Pavel Machek
2016-05-16 15:06 ` Pavel Machek
2016-05-24 19:49 ` Pavel Machek
2016-05-24 19:49 ` Pavel Machek
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